Not what I first expected… but there's a hint hiding there though… Why is the BaseTemplate column right aligned as if was numeric?

If we take the above script and pipe it to Get-Member we find that BaseTemplate is not a string! It's an object of some kind. It's an SPListTemplateType object!

So let's see what that is… Doing a Bing on Microsoft.SharePoint.SPListTemplateType reveals that it is an enumeration, which internally is a number. If you look at the list in the MSDN article you will see both the text and numeric values of the base types.

What we need is the display text for the enumeration, and we can get that by using the ToString() method. As that would then be an expression, we need to add the annoying curly brackets and the $_. notation.